Transmission systems are a vital link in the powertrain of any vehicle. In vehicles, the purpose of the transmission system is to employ gears of various sizes to provide an engine with a mechanical advantage over the driving wheels. Maintaining good lubrication is a key to proper operation and long-lasting transmission life. Significant problems often result if the amount of oil falls below minimum levels or if the oil becomes too dirty.
Transmission system lubricants include single and multiple viscosity gear oils, engine oils, and automatic transmission fluids. Such fluids can be petroleum-based, partially synthetic, or entirely synthetic. To reduce wear and friction inside a transmission, some lubricants are further mixed with friction modifiers or other additives.
Proper flow characteristics of the fluid are also important in transmission operation. If the fluid flow is inadequate, the chances of a leak increases, parts may prematurely wear due to a lack of adequate lubrication, system pressure will be reduced, and overall hydraulic control will be less effective.
When a transmission is in use, especially in harsher applications, such as when towing or undergoing continual stop-and-go movements, the oil or lubricant can often pick up shavings and other particles. While the majority of the particles in the transmission are encountered in the first several thousand miles of operation, activities such as the snubbing of clutching teeth can cause such particles to exist over the life of the unit. Accordingly, it is recommended that the oil or lubricant be changed periodically, and generally no less frequently than as specified by the manufacturer. For most transmission lubrication systems, the procedure necessarily involves removing an oil pan to drain the transmission lubricant, although some transmission pans include a drain plug for such a purpose.
To provide additional protection for the system, a filter or screen is often attached to a valve body located above the oil pan. Conventional filters are made of paper or fabric, and are generally held in place by screws, clips, or bolts. Unfortunately, in most conventional transmission lubrication systems, the transmission oil drain pan must be removed and the oil in the system drained before the filter can be unbolted from the valve body to be inspected and/or replaced. With the great amount of work and inconvenience involved with accessing conventional transmission filters, such filters are rarely inspected and/or replaced as part of a preventative maintenance effort. Further, because a significant portion of the wear on a transmission occurs during the first several thousand miles of operation, most conventional filters are designed for the initial "break-in" period of the transmission, not for future maintenance over the life of the system.
Because of the effort and difficulty involved with maintaining conventional transmission systems, there is a need in the industry for an oil filtration system having a filter that can be more easily accessed, inspected and/or replaced--without requiring the draining of a significant amount of the oil or lubricant from the system.